Doubling cookies or halving a casserole sounds simple until you are dividing 3/4 cup by two at the counter. This recipe scaler does the math for every line at once and then rounds each amount to a measure you can actually use, switching units when that makes things easier, so 12 tablespoons becomes ¾ cup and 3 teaspoons becomes 1 tablespoon.
How to use the recipe scaler
- Paste or type your ingredients, one per line, each starting with its amount (for example 1 1/2 cups flour or 200 g sugar).
- Choose to scale by servings (enter what the recipe makes and what you want) or by a multiplier such as 0.5 or 2.
- Leave Switch to easier units on to convert between teaspoons, tablespoons and cups, grams and kilograms, or ounces and pounds when the result reads better. Turn it off to keep every line in its original unit.
- Copy the scaled list. Lines without a leading amount, such as salt to taste, are kept as they are.
How recipe scaling works
US volume amounts are converted to teaspoons first (1 tablespoon = 3 teaspoons, 1 cup = 48 teaspoons), scaled, and then expressed in the handiest unit: cups for a quarter cup or more, tablespoons for at least 1 tablespoon, otherwise teaspoons. Cups are rounded to the nearest eighth or third, tablespoons to the nearest half and teaspoons to the nearest eighth.
Worked example
A cookie recipe makes 24 and you want 36, a factor of 36 ÷ 24 = 1.5:
2 ¼ cups flour × 1.5 = 3.375 cups → 3⅜ cups (3¼ cups + 2 tbsp)
¾ cup granulated sugar × 1.5 = 1.125 cups → 1⅛ cups (1 cup + 2 tbsp)
2 tsp vanilla × 1.5 = 3 tsp → 1 tbsp
2 large eggs × 1.5 = 3 eggs; 1 cup butter × 1.5 = 1½ cups
Handy kitchen equivalents
| Measure | Equals |
|---|---|
| 1 tablespoon | 3 teaspoons |
| ⅛ cup | 2 tablespoons |
| ¼ cup | 4 tablespoons |
| ⅓ cup | 5 tablespoons + 1 teaspoon |
| ½ cup | 8 tablespoons |
| 1 cup | 16 tablespoons = 8 fl oz ≈ 237 mL |
| 1 pound | 16 ounces ≈ 454 g |
Odd eighths of a cup (⅜, ⅝, ⅞) are not on most measuring-cup sets, so the scaler adds the cup-plus-tablespoons version in brackets.
Tips for scaling well
Weigh when you can
Flour, sugar and other dry goods vary a lot by how they are scooped; a cup of flour can weigh anywhere from about 120 to 150 grams. If the recipe gives grams, scaling by weight is more reliable, and the scaler keeps metric weights in grams or kilograms.
Mind the pan
Scaling ingredients by 1.5 also needs about 1.5 times the pan area. Pan area grows with the square of the side, so going from an 8-inch square (64 sq in) to a 9-by-13 (117 sq in) is roughly a 1.8× increase. If the pan is deeper than before, lower the oven temperature slightly and bake longer.
Treat eggs and leavening with care
Eggs do not divide neatly. For fractions, beat the eggs and measure about 3 tablespoons per large egg. Baking soda, baking powder and yeast scale fine for doubling or halving; for larger jumps, check the result in a small test batch.
Batch rather than multiply big
For very large quantities, making several batches of the original size is often more reliable than one giant batch, especially for doughs and batters that depend on mixing time.
For conversions beyond scaling, try the cooking converter, the cups to milliliters converter or the grams to ounces converter. The fraction calculator helps with any odd amounts you want to check by hand.
Frequently asked questions
How do I scale a recipe by servings?
Divide the servings you want by the servings the recipe makes to get a scale factor, then multiply every ingredient by it. Going from 24 to 36 cookies is a factor of 1.5, so 2 cups of flour becomes 3 cups.
What do I do with half an egg?
Beat the egg and measure. A large egg is about 3 tablespoons (roughly 50 grams) without the shell, so half is about 1½ tablespoons. In many baked goods you can also round to the nearest whole egg when scaling up a lot.
Does baking time change when I double a recipe?
Usually, yes, if you bake it in a deeper or larger pan. Thicker batters take longer to cook through, so start checking at the original time and continue in short intervals. Baking in two pans of the original size keeps timing the same.
Should I scale salt, spices and leavening exactly?
For modest changes, yes. For large increases (triple and beyond), many cooks start with a little less salt, strong spices and baking soda or powder, taste, and adjust, because flavors and rise do not always scale perfectly.
Which ingredient formats does the scaler understand?
Lines that start with an amount: whole numbers, decimals, fractions like 3/4, mixed numbers like 1 1/2, unicode fractions like ½, and ranges like 2-3. It recognizes US and metric units such as cups, tbsp, tsp, oz, lb, g, kg, mL and L.